1. Field of the Invention
The present invention relates to organic chemistry and more particularly to the processing of aromatic hydrocarbons. Still more particularly, the present invention relates to processes for preparing trinitrotoluene (TNT).
2. Brief Description of Prior Developments
In the prior art process of preparing TNT, one mole of 2,4-dinitrotoluene is added to a mixture of 3 moles of concentrated nitric acid and 5 moles of concentrated sulfuric acid. The mixture is heated to 130° C. for 2 hours. The dark red brown viscous solution is poured into a large volume of water and the crude TNT product is isolated by filtration, then purified by washing with sodium sulfite solution which affords a “red water” waste containing TNT isomers and impurities. The TNT is then washed with hot water. The yield of TNT is approximately 84%
A disadvantage of this prior art process is due to the fact that a large volume of concentrated sulfuric acid is used. The acid mixture is highly corrosive. The initial crude TNT is impure and must be purified by sulfite washing which produces a environmentally hazardous waste. The resulting large volume of spent sulfuric acid must be recovered and purified for reuse.